GPT
If you want to create partitions larger than 2TB you'll have to use GTP partitioning system instead of classical MBR. Note that you BIOS knows only MBR partitioning schema and will not likely boot from a GTP partition.
Creating Partitions
You'll need to use parted to create the partitions since fdisk only know to work with MBR. The next command will open a parted shell, you'll need to replace /dev/sda with the drive that you want to partition.
parted /dev/sda
The next commands should be typed int the parted shell.
WARNING: By running this commands you will delete you partition schema and won't be able to access the information that was stored on the disk (if any).
(parted) mklabel gpt <-- This one creates a empty partition table on the disk
(parted) print <-- List some information about the current partition table, size of the disc
(parted) mkpart primary 0 3000GB <--- Creates a partition starting from the beginning trough the 3000GB location (parted) mkpart primary 3000GB 5000GB <--- Creates another partition starting from the 3000GB locations to the 5000GB location
(parted) quit <-- Exit the parted shell
After doing the previous command, you should have created two partitions, a 3TB and a 2TB one. In order for udev to create /dev/sda1 and /dev/sda2 devices associated with the partitions, you need to run the next command or reboot your computer:
partprobe /dev/sda
Formating the partitions
Except of partition creation you won't see any difference between GPT and MBR in linux. So for formatting you can do it the same way as you would format any other discs. For example:
mkfs.ext3 /dev/sda1